The medical crisis among men detained on Manus Island has been overshadowed by the children's health crisis on Nauru, refugees and their advocates say.

Refugees on Manus Island Photo: Supplied

An awareness campaign and legal action has forced the Australian government to transfer dozens of sick refugee children from Nauru this year but about 30 remain on the island.

More than 600 men remain in indefinite detention on Papua New Guinea's Manus Island, their number recently bolstered by about 35 men sent back from Port Moresby because of the APEC summit.

In the capital for medical treatment that for many never eventuated after months of waiting, the refugees had to make way so their hospital can treat any APEC delegates who become sick.

While some refugees have been told they will be returned to Port Moresby in December, the advocate Ian Rintoul said sick refugees faced a month without treatment.

"Some of the people who have got ongoing things that need monitoring and treatment have been sent back to Manus where they're not going to get any of that for the next month," Mr Rintoul said.

"The people who have been presumably deemed too sick to be transferred back to Manus are now effectively locked down in Granville motel without any hospital appointments," he said.

"So we can envisage a month where the medical crisis on Manus and in Port Moresby is just going to get worse."

A sign outside Pacific International Hospital in Port Moresby prior to the APEC summit. Photo: Supplied

Among the men back on Manus is Kurdish refugee Benham Satah, who said four suicidal refugees were in the intensive care ward at Pacific International Hospital.

One, a sick Iraqi man who previously swallowed razor blades and a pair of nail clippers, was kept in Port Moresby after a gruesome act of self harm, Mr Satah said.

"He's in a very bad situation. He's lost lots of blood after he did self harm and not mentally well at all. He did a very big cut in his head. He lost so much blood that he was so weak that he couldn't walk and then he collapsed and I think his nose is also broken," he said.

"He has been in Port Moresby for a long time - actually three times for the same medical issue that never got proper treatment."

Many more sick men await transfer or treatment on Manus, where former refugee case worker Nicole Judge recently returned, five years after quitting offshore detention.

Appalled by inhuman, abusive treatment of detainees, Ms Judge said the refugees' health had dramatically deteriorated since she last saw them.

"Some of the people have open sores that are weeping, all over their bodies and they don't know what it is, which alarms us as advocates because that is what Hamid Khazaei had and he ended up dying of septicemia," Ms Judge said.

The catatonic refugee at Lorengau hospital. Photo: Supplied

"Other people are very distressed and suicidal and attempting suicide every few days," she said.

"Other people have bleeding, these are young men who are having this bleeding and they don't know why. So there are digestion problems and they're not being told what's wrong with them or what they can do to treat them. They're just being left on Manus."

The Kurdish journalist and Manus Island refugee Behrouz Boochani said seven refugees had attempted suicide over the last 10 days.

A catatonic refugee, who has refused food for 10 days and is now refusing water, could not be adequately treated at the island's hospital, Mr Boochani said.

The campaign for refugee children on Nauru had made adult refugees feel ignored, he added.

"The Kids off Nauru campaign has had a negative impact on the refugees on Manus Island and I am sure has a negative impact on the adult people on Nauru because people think that the refugees movement forget about them and they feel they are forgotten people."

Mr Rintoul agreed that the health crisis on Manus was being overlooked.

"There's no doubt that it's been overshadowed in the same kind of way that the health crisis for the adults on Nauru has been overshadowed," he said.

"There's no doubt that there are acute cases, both on Nauru and on Manus that require very urgent responses from the Australian Border Force."